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Design >> High-Power Design >> supply bypassing
https://designers-guide.org/forum/YaBB.pl?num=1314761976

Message started by WU CHIH-CHIANG on Aug 30^th, 2011, 8:39pm

Title: supply bypassing
Post by WU CHIH-CHIANG on Aug 30^th, 2011, 8:39pm

Proper bypass capacitors must be chosen to protect the device from voltage transients during switching transitions.Two capacitors should be used directly at the driver from power supply to ground to prevent damage or improper operation due to voltage transients during switching: a large cap (nominally 10uF) for low frequencies, and a small cap (nominally 0.1uF) for high frequencies. The actual value of the capacitors depends upon the noise characteristics of the power supply.
Then my question is what is the proper value of capacitors.
How can I calculate those value.
In fact,I feel puzzle in ''ST IRF630 data sheet''.
In ST IRF630 data sheet, the circuit of the switching times test circuits for resistive load.What is the purpose of the two capacitor(2200uF,3.3uF) bypass the VDD.Bypass filter or other purpose? If its main purpose is Bypass filter ,what range of frequency they filter.Please give me the detailed information.Thanks!,
''ST IRF630 data sheet'' : http://www.datasheetcatalog.org/datasheet/stmicroelectronics/3006.pdf